CMS OP fails validation

When setting paragraphs to 'justify' the CMS inserts a 'align = justify' into the <p> tag. This does not comply with standards as the 'align' tag is depreciated. I have tried manually changing the HTML within the CMS to style="text-align:justify", but the CMS over-writes this with its <p align='justify'>. As I promise all of my clients that their sites will comply to standards, this is causing a problem.

Any suggestions of how to modify this? Where in the js code could this be changed? setting text-align within the css is one solution, but this then affects the CMS presentation for those who edit the site content via the CMS.